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| Targets |
CREBtide TFA targets protein kinase A (PKA) and cGMP-dependent protein kinase (cGK) as a substrate. The peptide is based on the phosphorylation sequence in delta-CREB, a spliced variant of CREB. The apparent Km of CREBtide phosphorylation by PKA is 3.9 μM, which is 10-fold lower than that of Kemptide (Km=39 μM), the synthetic peptide substrate most often employed for PKA measurement. The Vmax values are 12.4 μmol/(min·mg) for CREBtide and 9.8 μmol/(min·mg) for Kemptide.
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| ln Vitro |
delta-CREB is a spliced variant of cAMP response element binding protein (CREB). CREBtide (KRREILSRRPSYR), a synthetic peptide based on the phosphorylation sequence in delta-CREB. delta-CREB and CREBtide are tested as substrates of cAMP-dependent protein kinase (cAK). The apparent Km of CREBtide phosphorylation by cAK is 3.9 μM, which is 10-fold lower than that of Kemptide (Km=39 μM), the synthetic peptide substrate most often employed for cAK measurement. The Vmax values are 12.4 mumol/(min.mg) for CREBtide and 9.8 mumol/(min.mg) for Kemptide. The apparent Km of CREBtide phosphorylation by cGMP-dependent protein kinase (cGK) is 2.9 μM and the Vmax value is 3.2 mumol/(min.mg). Both delta-CREB and CREBtide are phosphorylated at a much slower rate by cGK as compared with cAK, implying that the high cAK/cGK specificity exhibits by delta-CREB is retained by the peptide[2].
In vitro, CREBtide TFA is used as a substrate to measure PKA and cGK activity. The apparent Km of CREBtide phosphorylation by cGK is 2.9 μM and the Vmax value is 3.2 μmol/(min·mg). Both delta-CREB and CREBtide are phosphorylated at a much slower rate by cGK as compared with PKA, implying that the high PKA/cGK specificity exhibited by delta-CREB is retained by the peptide. The peptide is used in kinase assays to quantify enzyme activity. |
| ln Vivo |
In vivo activity is not directly applicable for CREBtide TFA as it is a synthetic peptide substrate used in biochemical kinase assays, not a therapeutic compound. The peptide is used as a tool to study PKA and cGK activity in cell lysates or tissue homogenates. Its role is in the characterization of kinase activity rather than as a therapeutic agent.
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| Enzyme Assay |
Non-cellular enzyme assays using CREBtide TFA involve incubating the peptide with purified PKA or cGK in the presence of ATP. Phosphorylation of the peptide is measured by incorporating 32P-ATP and quantifying the phosphorylated product by scintillation counting or by using phospho-specific antibodies. The kinetic parameters (Km and Vmax) are determined from substrate concentration curves. These assays are used to characterize kinase activity and to screen for kinase inhibitors.
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| Cell Assay |
In vitro cellular experiments using CREBtide TFA are limited due to the peptide's inability to cross cell membranes efficiently. However, cell lysates can be prepared from treated cells, and PKA or cGK activity in the lysates can be measured using the peptide as a substrate. This approach allows researchers to assess the effects of test compounds on PKA or cGK activity in cellular contexts. Cells are treated with compounds of interest, lysed, and the lysates are incubated with the peptide to measure kinase activity.
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| Animal Protocol |
In vivo animal experiments using CREBtide TFA involve collecting tissue samples from animals and measuring PKA or cGK activity ex vivo using the peptide as a substrate. The peptide is incubated with tissue homogenates or lysates, and phosphorylation is quantified to assess kinase activity. This approach can be used to monitor changes in kinase activity in disease models or following drug treatment.
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| ADME/Pharmacokinetics |
CREBtide TFA has a molecular weight of 1716.99 (free acid). The peptide sequence is KRREILSRRPSYR. Purity is typically >98%. The compound is supplied as a TFA salt. It is stored as a powder at -20°C and protected from light. It is soluble in water and aqueous buffers. The compound is for research use only and not for human therapeutic applications.
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| Toxicity/Toxicokinetics |
Toxicity data for CREBtide TFA are limited as it is a research reagent used in kinase assays, not a therapeutic agent. Standard laboratory safety precautions should be followed when handling the peptide. The compound is for research use only and not for human therapeutic applications.
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| References |
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| Additional Infomation |
CREBtide TFA is a CREB-like peptide and a PKA substrate. A key reference is Colbran JL, et al. "cAMP-dependent protein kinase, but not the cGMP-dependent enzyme, rapidly phosphorylates delta-CREB, and a synthetic delta-CREB peptide." Biochem Cell Biol. 1992. The peptide shows higher affinity for PKA compared to Kemptide. All products are for research use only.
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| Molecular Formula |
C73H129N29O19.XC2HF3O2
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| Molecular Weight |
1716.99 (free acid)
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| Appearance |
White to off-white solid powder
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| HS Tariff Code |
2934.99.9001
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| Storage |
Powder -20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month Note: Please store this product in a sealed and protected environment, avoid exposure to moisture. |
| Shipping Condition |
Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)
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| Solubility (In Vitro) |
Typically soluble in DMSO (e.g. 10 mM)
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| Solubility (In Vivo) |
Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples.
Injection Formulations
Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline)(e.g. IP/IV/IM/SC) *Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution. Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline) Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil) Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals). View More
Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)] Oral Formulations
Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium) Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals). View More
Oral Formulation 3: Dissolved in PEG400 (Please use freshly prepared in vivo formulations for optimal results.) |
Calculation results
Working concentration： mg/mL；
Method for preparing DMSO stock solution： mg drug pre-dissolved in μL DMSO (stock solution concentration mg/mL). Please contact us first if the concentration exceeds the DMSO solubility of the batch of drug.
Method for preparing in vivo formulation:：Take μL DMSO stock solution, next add μL PEG300, mix and clarify, next addμL Tween 80, mix and clarify, next add μL ddH2O，mix and clarify.
(1) Please be sure that the solution is clear before the addition of next solvent. Dissolution methods like vortex, ultrasound or warming and heat may be used to aid dissolving.
(2) Be sure to add the solvent(s) in order.
Products are for research use only; We do not sell to patients
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